A Simple On-line SHE PWM With Extension to Six Step Mode in Two-Level Inverters

The Selective Harmonic Elimination (SHE) PWM technique has become a significant PWM method for less switching loss for voltage source inverter. For off-line approach, the various sets of commutation angles in relation to modulation index are commonly determined in advance and look-up tables are required. This trouble can be avoided in on-line approach. The paper presents a simple on-line SHE PWM method with linear control of the fundamental voltage, including SHE-overmodulation range using the Principle Control between limit angular trajectories. The method has been mathematical described. The simulation and experimental results have been implemented to confirm the validity of the proposed method.